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G. ANDERSSON. PNEUMAUC ROCK DRILLING MACHINE. APPLlCAT|0N man Ammo. ma.

Patented .Dec. 30, 1919;

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G. ANDERSSON. PNEUMATIC ROCK nn ume MACHINE. V

APPHCATION' HLED APR. 10. me.

PatentediDec. 30,1919.

, 2 -S NFETS-SHEET 2.

I W)? Y UNITED STATES PATENT OFFICE.

GUSTAF ANDERSSON, OF STOCKHOLM, SWEDEN.

PNEUMATIC ROCK-DRILLING MACHINE.

Application filed April 10, 1918.

To all whom it may concern:

Be it known that I, GUs'rAr Anonnssoiv, a citizen of the Kingdom of Sweden, residing at Stockholm, Sweden, have invented new and useful Improvements in Pneumatic Itock-Drilling Machines, of which the following is a specification.

This invention relates to pneumatic rock drills and is specially adapted for use wlth pneumatic rock drilling machines provided with means for scavenging the bore-hole by means of water supplied through the hollow bit.

An object of the invention is to provide a pneumatic rock drilling machine in which the scavenging water is supplied to the bit in such manner that no water can enter the cylinder containing the percussion mechanism from the water conduit leading to the bit.

The invention will be more fully understood in connection with the description of the accompanying drawings, whereinlike characters of reference indicate the same parts in the difierent views.

Figure 1 is an axial section of the fore end of a pneumatic rock drilling machine. Fig. 2 is a cross-section on line 22 in Fig. 1. Fig. 3 is an axial section of a similar machine showing another type thereof. Fig. 4: is a detail sectional view of the ratchet mechanism of the latter machine.

Referring to Figs. 1 and 2, 1 is the cylinder, 2 the piston or hammer, 3 the anvil block situated between the piston 2 and the bit at, and 5 is the bit holder. The bit 4- is provided with a channel or passage 6 passing centrally through the same, and in the anvil block 3 there is disposed in a well-known manner a corresponding passage 7 forming in part an extension of the passage 6 and deviating in part sidewise to the side-surface of the anvil block. The passage 7 communicates outside the anvil block with a conduit 8 supplying the scavenging water to the bore-hole. Inserted in said conduit 8 and bearing against the anvil block 3 is a nipple 9 connected by means of a screwgland 10 with the bit-holder 5. The end 11 of the nipple 9 adjacent to the anvil block 3 is formed as a socket, and inserted in said socket is a packing 12 provided with a cen tral aperture 13 communicating with the bore 14 of the nipple 9 and the passage 7. Owing to the pressure of water acting on the outer side 15 of the packing 12, the latter Specification of Letters Iatent.

Patented Dec. 30, 1919.

Serial No. 227,782.

fits tightly to the inside of the socket 11 and the anvil block 3.

In order to prevent turning of the anvil block 3 the latter has non-circular outline at the contact surface of the packing for instance by being provided with a flat surface 16 forming the seat of the packing 12.

By the aid of the arrangement described several advantages are obtained. Thus for instance, no lateral passages need be bored in the bit which has only to be cut oif to suitable length and hardened at the impact end, and on account thereof the durability of the portion of the bit inserted in the drill holder is unreduced. Further, leakage of the water from the passages leading to the borehole and the inconveniences connected with such leakage are effectively prevented, and, besides, a reliable guidance of the anvil block and an uninterrupted water jet are effected.

Figs. 3 and e illustrate another arrangement of the scavenging water conduit especially adapted to be used in connection with rock drilling machines having a rotary cylinder.

The rotary cylinder 1 is inclosed by an outer stationary casing 17 slidingly mounted in a guide 18 by means of a saddle 19, the longitudinal movement of the casing and the cylinder being eifected in well known manner by the aid of a screw 20 engaging the saddle 19. The rotary movement of the cylinder is obtained by the following or rangement.

Inserted in an extended portion 21 ofthe casing 17 is a piston 22 reciprocating under the action of the motive fluid of the drilling machine and pivotally connected with a ratchet socket 23, the teeth 24: of which are in engagement with spring-actuated pawls 25 pivotally mounted in a back-head 27 bolted to the cylinder 1. Thus, by the reciprocating movement of the piston 22, a stepwise rotary travel is imparted to the bit.

In this case the passage 26 supplying water to the borehole is located in the wall of the cylinder 1, fore and rear extensions 28 and 29 respectively of the passage 26 being disposed in the bit-holder 5 and the backhead 27 respectively and suitable packings 30 and 31 securing tight connection between the different parts of the water passage. The connection between the passage 28 and the passage 7 of the anvil block 3 is effected by a screw-nipple 32 of about the same construction as the nipple 9 in Figs. 1 and 2 and provided with a packing 33 similar to the packing 12.

The scavenging Water is introduced centrally or axially into the machine from a conduit 34. To this end a nozzle 35 rigidly connected or integral With the conduit 34: is inserted in the back-head 27, suitable packings being disposed between the stationary nozzle and the rotating back-head. By this arrangement the contactsurface between the rotary parts of the machine and the stationary Water supply conduit is reduced to a minimum, and owing thereto and to the location of the Water-passage and the packings inserted therein, leakage of Water from said passage to the cylinder is prevented.

Having now particularly described and ascertained the nature of my said invention and in What manner the same is to be performed, I declare that What I claim is:

1. In a rock drilling machine, the coinbination of a Working cylinder, a hollow bit, means supplying scavenging Water to the borehole through the bit, an anvil-block located at the inner end of the bit, a passage leading through the anvil block from the bit to the Water supply means, and packing bearing against a non-circular surface of the anvil-block and separating-the passage therein from the interior of the Working cylinder, substantially as and for the purpose set forth.

2. In a rock drilling machine, the combination 01": a rotating Working cylinder, a hollow bit, means supplying scavenging Water to the bore-hole through the bit and disposed in the wall of the cylinder, and an inlet passage communicating With said water supply means and located centrally in the rear end of the machine, substantially as and for the purpose set forth.

3. In a rock drilling machine the combination of a rotating Working cylinder, a hollOW bit, means supplying scavenging water to the bore-hole through the bit and disposed in the Wall oi the cylinder, and a nozzle communicating with said Water supply means and inserted centrally in the rear end of the machine, substantially as and for the purpose set forth.

4:. In a rock drilling machine, the combination of a rotating cylinder, a hollow bit, means supplying scavenging Water to the bore-hole through the bit, and disposed in the Wall of the cylinder, an anvil block located at the inner end of the bit, a passage leadin through the anvil block from the bit to t e Water supply means, and an inlet passage communicating with said Water supply means and located centrally in the rear end of the machine, substantially as and for the purpose set forth.

In testimony whereof I have signed my name.

GUSTAF AN DERSSON. 

